As is known in the art, power converters for supplying dc loads from a single-phase ac grid are used to power many electronic systems. Typical designs must operate on ac input voltage having a relatively wide range (e.g., 85-264 Vrms), and provide a (preferably regulated) dc output. Some applications require an isolated low-voltage dc output (e.g., 24 V). The efficiency of a power converter is also important for many applications (e.g., >95% for a non-isolated output or 90-95% for isolated conversion to low voltage), as is ac line power factor (e.g., >0.9 or >0.95).
Conventional power converters typically operate at relatively low switching frequencies (typically on the order of 200 kHz or below) with associated low power densities (˜10 W/in3 or below). Moreover, at such switching frequencies, the magnetic energy storage components and filters needed for power converters may be relatively large and expensive. Thus, the size and cost of conventional power converters is often dominated by the requirements of the necessary magnetic components.